Astronomy. Astrophysics. The first search for variable stars in the open cluster NGC 6253 and its surrounding field,
|
|
- Baldric Martin
- 5 years ago
- Views:
Transcription
1 A&A 509, A17 (2010) DOI: / / c ESO 2010 Astronomy & Astrophysics The first search for variable stars in the open cluster NGC 6253 and its surrounding field, F. De Marchi 1,2, E. Poretti 3,M.Montalto 4,5,S.Desidera 6, and G. Piotto 1 1 Dipartimento di Astronomia, Università di Padova, Vicolo dell Osservatorio 2, Padova, Italy fdemarchi@science.unitn.it 2 Dipartimento di Fisica, Università di Trento, Via Sommarive 14, Povo (TN), Italy 3 INAF - Osservatorio Astronomico di Brera, Via E. Bianchi 46, Merate (LC), Italy 4 Universitaets-Sternwarte der Ludwig-Maximilians-Universitaet, Scheinerstr. 1, Muenchen, Germany 5 Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstr., Garching bei Muenchen, Germany 6 INAF - Osservatorio Astronomico di Padova, Vicolo dell Osservatorio 5, Padova, Italy Received 22 May 2009 / Accepted 30 September 2009 ABSTRACT Aims. This work presents the first high-precision variability survey in the field of the intermediate-age, metal-rich open cluster NGC Clusters of this type are benchmarks for stellar evolution models. Methods. Continuous photometric monitoring of the cluster and its surrounding field was performed over a time span of ten nights using the Wide Field Imager mounted at the ESO-MPI 2.2 m telescope. High-quality timeseries, each composed of about 800 datapoints, were obtained for stars using ISIS and DAOPHOT packages. Candidate members were selected by using the colour magnitude diagrams and period-luminosity-colour relations. Membership probabilities based on the proper motions were also used. The membership of all the variables discovered within a radius of 8 from the centre is discussed by comparing the incidence of the classes in the cluster direction and in the surrounding field. Results. We discovered 595 variables and we also characterized most of them providing their variability classes, periods, and amplitudes. The sample is complete for short periods: we classified 20 pulsating variables, 225 contact systems, 99 eclipsing systems (22 β Lyr type, 59 β Per type, 18 RS CVn type), and 77 rotational variables. The time-baseline hampered the precise characterization of 173 variables with periods longer than 4 5 days. Moreover, we found a cataclysmic system undergoing an outburst of about 2.5 mag. We propose a list of 35 variable stars as probable members of NGC Key words. starspots stars: statistics stars: variables: general binaries: eclipsing novae, cataclysmic variables open clusters and associations: individual: NGC Introduction NGC 6253 and NGC 6791 are the only open clusters whose metallicities above [Fe/H] =+0.3 were confirmed by spectroscopic analyses (Carretta et al. 2000, 2007; Sestito et al. 2007). Therefore, these clusters are of special interest in several fields, e.g., as benchmarks for stellar evolution and stellar population models and as targets for the search for extrasolar planets. We observed both clusters in the framework of our project looking for transiting planets in super-metal-rich open clusters. The results obtained on NGC 6791 were presented by Montalto et al. (2007). We also performed a 10-night observing campaign on NGC 6253 with the same purposes as for NGC In the first paper based on our new investigation, Montalto et al. (2009) obtained broad band photometry and astrometry for stars within 30 arcmin from the cluster. Images from ESO archive Based on observation made at the European Southern Observatory, La Silla, Chile, Proposal 073.C Timeseries and light curves are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr ( ) or via (Momany et al. 2001) were also used to derive relative proper motions and then distinguish between field stars and cluster members. The availability of the astrometric cluster memberships and the photometric quality of the new data allowed new, independent determinations of the cluster s main parameters. Indeed, the determinations of the NGC 6253 parameters are affected by larger uncertainties because of the cluster s projection toward a very rich stellar field fairly close to the galactic centre (l = deg, b = 6.25 deg). Systematic differences in the photometric calibrations of different datasets have been found (Bragaglia et al. 1997; Piatti et al. 1998; Sagar et al. 2001; Twarog et al. 2003; Anthony-Twarog et al. 2007). In this paper we adopt the values of the distance modulus and of the reddenings obtained by Montalto et al. (2009) using the technique of the isochrone fitting, i.e., (m M) V = ± 0.10 mag, E(B V) = 0.15 ± 0.02 mag and E(V I) = 0.25 ± 0.02 mag. These values are also consistent with a weighted mean of all the determinations. The cluster age is about 3.5 Gyr (Montalto et al. 2009). Our project gives the possibility of studying stellar variability in super-metal-rich stars using high-quality data (DeMarchi et al. 2007). Since no variability survey on NGC 6253 has previously been performed, we characterize the variable stars in NGC 6253 and in its surrounding field for the first time. To do Article published by EDP Sciences Page 1 of 18
2 Table 1. The observation log for each night and limits of the field of view. A&A 509, A17 (2010) Date t start t end Date t start t end [Year 2004] [HJD ] [Year 2004] [HJD ] June, June, June, June, June, June, June, June, June, June, α min 16 h 56 m 41.6 α max 17 h 00 m 24.7 δ min δ max that, we started from the new findings and calibrations obtained by Montalto et al. (2009) so we refer the reader to that paper for a more detailed explanation of the methodologies applied to determine the properties and the fundamental parameters of the cluster. 2. Observations and data reduction NGC 6253 was observed for 10 consecutive nights (from June 13, 2004 to June 22, 2004) using the Wide-Field Imager (WFI) mounted at the ESO-MPI 2.2 m telescope, La Silla, Chile. The WFI instrument includes a mosaic of eight 2k 4k CCDs. The pixel scale is arcsec/pixel. In total, 45.3 h of observation were collected, mainly in the R filter. A few deep images in the B, V, andi filters were also acquired to construct colour magnitude diagrams (CMDs), along with a standard field to allow the calibration of the data. In total 918 images of the cluster were obtained, with a mean exposure time of 178 s. Table 1 reports the journal of observations and Fig. 1 shows a WFI image of NGC Since the the size of each chip is 8 in right ascension and 16 in declination, we centered the cluster on one chip to minimize the loss of stars between chips. Observations and data reduction to derive the calibrated photometry and the CMDs of the cluster are described in more detail in Montalto et al. (2009). The procedure to derive the light curves uses both ISIS 2.2 (Alard & Lupton 1998; Alard 2000) and DAOPHOT II (Stetson 1998) packages, as described in Montalto et al. (2007). The length of the observing nights (more than 0.32 d in 7 cases and more than 0.40 d in 5 cases, see Table 1) reduced the height of the aliases situated at ±1 d 1 from the central peak down to below 60% of the power (Fig. 2, upper panel). Moreover, the light curves are very dense and their shape clearly defined on each night (Fig. 2, middle panel). Both these facts made the period detection quite straightforward, not only in the case of high-amplitude variables, but most of time also for smallamplitude, short-period variable stars. As can be noted in Fig. 1, our survey covers a much larger field of view than the previous ones ( arcmin 2 by Bragaglia et al. 1997, arcmin 2 by Piatti et al. 1998). We could also identify new variable stars in a wide part of the surrounding field. The ISIS 2.2. and DAOPHOT II packages returned a photometric precision well below 0.01 mag in the magnitude range 14 R 19. A plot of the standard errors of the mean magnitudes in different filters is shown in Fig. 1 in Montalto et al. (2009). Stars brighter than the turn-off magnitude (V = 14.5) are saturated in our photometry and cannot be studied. In particular, this constraint hampers the study of the variability of the blue stragglers, as performed by De Marchi (2008)inthe more favourable case of NGC Fig. 1. Image of the WFI field (32 32 arcmin 2 ). Solid lines represent the edges of the arcmin 2 box surveyed by Bragaglia et al. (1997). Large points are stars with membership probabilities (available only for stars located in chip 2) greater than 90%. Chips are numbered from 1 (top right)to8(bottom right). Fig. 2. Upper panel: spectral window of the timeseries of the variable stars in NGC Middle panel: example of an unfolded light curve: the high-amplitude δ Sct star _6. Bottom panel: histograms of the standard deviations of the least-squares fit on the light curves of the periodic variables. 3. Cluster membership NGC 6253 is a relatively small cluster, but Bragaglia et al. (1997) noticed the necessity of moving 8 from the cluster centre to find a legitimate external field. We followed this prescription and we adopted the centre coordinates given by Bragaglia et al. (1997). Page 2 of 18
3 F. De Marchi et al.: Variable stars in NGC 6253 The measured stars are indicated by small points, the 150 stars with membership probability (hereafter MP) greater than 90% are highlighted with larger black points. MPs were calculated in Montalto et al. (2009) following the approach proposed by Vasilevskis et al. (1958): MP =Φ c /(Φ c +Φ f ) (1) where Φ c and Φ f are the distribution of cluster and field stars in the diagram of the proper motions, respectively. These distributions are typically represented as Gaussian functions. The distribution of the cluster stars has a narrow peak centered at μ α = μ δ = 0, while the distribution of field stars is much broader. For the given candidate member, the calculation of the MP was performed by selecting a surrounding sample of a 2.5 mag range centered on the candidate s position. In such a way the local sample stars compensate for the effect of a magnitude dependence of the cluster-to-field star ratio. When constructing a V MP diagram, the stars belonging to the cluster occupy a well-defined region (see Fig. 4 in Montalto et al. 2009). We require the probable member clusters to have MP > 90% at V = 12.5andMP> 50% at V = Since the determination of the MPs is a differential process and the cluster is almost completely included in chip 2, the MPs are reliable only for stars belonging to this chip and brighter than V = 18. Looking at the distribution of the stars with a high MP we can infer that some members of the cluster might also be present in chips 1 and The variable stars 4.1. Detection The ISIS 2.2 and DAOPHOT II packages allowed us to extract the first list of suspected variable stars from the full database of timeseries. This list was validated and shortened by calculating the parameters related to the reduction of the initial variance obtained by introducing trial periodic terms. These parameters are the reduction factor (Vaníček 1971) and the coefficient of spectral correlation (Ferraz-Mello 1981). As in the case of NGC 6971 (De Marchi et al. 2007), we could separate shortand long- period variable stars by introducing a parameter that is more sensitive to the night-to-night variations. Tests on the significance of the detected periodicities (e.g., signal-to-noise ratio above 4.0 in amplitude) allowed us to get a more defined sample of real variable stars. A few objects whose variability appears to stem from photometric artefacts (e.g. eclipse-like features occurring exactly at the same time on the second night) were removed from the list. These spurious photometric effects are usually corrected when applying to the light-curve algorithms such as the one developed by Tamuz et al. (2005). However, we noticed that the application of this algorithm degrades the precision of the variable star photometry. Therefore, being interested in much greater light variations than the tiny photometric effect of a planetary transit, we decided to analyse the light curves before applying the algorithm. We identified 595 variable stars at the end of our process, whose timeseries are composed of about 800 datapoints. To identify them we used the five-digit number assigned by our customized package package, followed by the number of the chip that the star belongs to. The timeseries are available at the Centre de données astronomiques de Strasbourg (CDS). Table 2. Inventory of the variables found in NGC 6253 and its surrounding area. Type Number of variables all chips r < 8 candidate probable members members RR Lyrae δ Scuti β Cep HADS EW-type EB-type EA-type RS CVn U Geminorum Rotationals Long period Classification The timeseries of the 595 variable stars were analysed in frequency by using the least-squares iterative sine-wave search (Vaníček 1971) and the Phase Dispersion Minimization (Stellingwerf 1978) methods. The periods were refined by means of a least-squares procedure (MTRAP, Carpino et al. 1987); their error bars are in the range d. The bottom panel of Fig. 2 shows the distribution of the standard deviations of the least-squares fits, indicating a median precision of mag. We could show amplitudes of light variability down to the 0.01 mag level. At this level, rotational variables could be separated from pulsating variables on the basis of the period values and of the Fourier parameters alone (Poretti 2001). On the other hand, it is very difficult to disentangle rotational from eclipsing variables. To distinguish rotational variables from contact binaries, we referred to the degree of asymmetry of the double-wave light curves and to the occurrence of the minima at phases 0.00 and Of course, we cannot rule out that a small fraction of the variables classified as rotational variables might be actually contact systems showing grazing eclipses or viceversa. We considered two classes of rotational variables, RO1 and RO2 stars. RO1 stars show a light curve characterized by a single wave, which is often asymmetrical. RO2 stars show a more complicated curve composed of two waves having unequal amplitude and duration. This light curve is comes from two (groups of) spots located at different latitudes that remain visible to the observer during different fractions of the rotational period. In some cases these spotted stars are observed in eclipsing systems, the so-called RS CVn variables. Other cases of eclipsing systems are contact (W UMa variables, EW), semi-detached (β Lyr variables, EB), and detached systems (Algol variables, EA) binaries. In some cases it was very difficult to distinguish between EW system showing grazing eclipses and rotational variables. We also identified three different classes of pulsating variables, i.e., RR Lyr, δ Sct and high-amplitude δ Sct (HADS) stars. In both cases, eclipsing binaries and pulsating variables, the very good spectral window (Fig. 2) made the period detection quite straightforward. On the other hand, defining the periods longer than 4 5 d was not easy. In particular it was impossible for periods longer than 10 d and we simply classify these stars as long period (LON) variables. These stars are mostly rotational variables. The summary classification of the entire sample is reported in Table 2. TablesA.1 A.8 list the members of each class giving the identifier in the Montalto et al. (2007) catalogue, the coordinates, the photometry, the epoch of maximum or Page 3 of 18
4 A&A 509, A17 (2010) minimum brightness (HJD ), the period, the amplitude, the distance, and the MP values. Uncertain MP values (stars with V > 18, often close to the chip borders) are marked with an asterisk. The catalogue of the light curves of the periodic variables is available at the CDS. We paid particular attention to the variables located within 8 from the cluster centre; in any cases no variable with MP larger than 50% was found at a greater distance. If the MP is not available (stars near the edges of chip 2 or stars fainter than V = 18), the membership is estimated from their location on the B V vs. V and V I vs. V CMDs. Moreover, for pulsating variables and contact binaries with unknown membership, our conclusions are based on the applications of the usual period luminosity (P L) and period luminosity colour (P L C) relations Pulsating variables The only pulsating variable located at less than 8 from the centre is the RRab star 10540_2. Its MP is quite high, but it is clearly too faint (V = 17.39) to belong to the cluster. Amongst the other four RR Lyr stars, 15578_7 is a new galactic Blazhko variable. Twelve variables show an amplitude smaller than 0.06 mag; since they have a very short period (less than 0.10 d), we can rule out their being rotational variables. All the B V values except one range from 0.42 to 0.79 mag, mostly between 0.50 and This interval, taking the reddening E(B V) = 0.15 mag into account, suggests their classification as δ Sct stars. The remaining low-amplitude variable shows (B V) = 0.084: it probably belongs to the β Cep class. Four variables show a larger amplitude (more than 0.09 mag) and the asymmetric shape of the light curve typical for highamplitude δ Sct stars. By using the new period-luminosity relation derived by Poretti et al. (2008), no doubt is left on the fact that all these variables do not belong to NCG Finally, none of the pulsating variables is a member of NGC 6253, since they are all located well beyond the cluster Contact binaries We have 50 contact binaries located within the 8 radius and the (B V) and(v I) colours are both available for 44 binaries, while only the (V I) colours are available for 6 of them. For these stars it is possible to apply the P L C relations given by Rucinski (2003) and compare the resulting distance moduli with that of the cluster, obtained by isochrone fitting (Montalto et al. 2009). The errors on the distance moduli are calculated by considering the uncertainties on the mean B V and V I colours. It must also be taken into account that, since our light curves are in the R band, we cannot know the exact value V max of the magnitude at maximum brightness required by the Rucinski (2003) calibrations. We estimated V max as (V mean R mean )+R max ; i.e., we assumed that the colour of these binary systems does not change during the orbital period since the components have a very similar temperature. An estimate of the membership of the objects can be obtained using the CMDs (Fig. 3, top row), the MPs based on the proper motions, and the two P L C relations (Fig. 3, bottom row). The fiducial lines shown in the CMDs are obtained by selecting points at different magnitudes along the Main Sequences, both from the observations described here and from Bragaglia et al. (1997). We could select a list of 13 candidate members for which one of the above criteria is satisfied (Table A.9). We note that 23188_2 and 10853_2 satisfy all the membership criteria and then are very likely cluster members. The positioninthecmdsandthep L C relations also suggest that 01015_2 is a cluster member, but this hint is not supported by the MP, which is very small. The case of 09268_2 is the opposite: it has also a fairly large MP, but the other indicators suggest that is is more probably located between the Sun and the cluster. Unfortunately, none of the remaining cases gives us enough confidence on a cluster membership. We can tackle the problem of cluster membership in an indirect way. In the surrounding field we found 175 EW binaries, with an incidence of 0.21 EW arcmin 2. Therefore, we should have 42 field EW-stars superposed on the cluster. Since we found 50 stars (Table 2), the excess is only marginally significant. We have only two well-established memberships; therefore, we can reasonably estimate that very few contact binaries (up to six) among the remaining 11 candidates listed in Table A.9 actually belong to NGC This clue is confirmed by the candidates do not match the photometric criteria very well (Table A.9). In NGC 6791 we found three well-established and five likely EW-members (De Marchi et al. 2007), i.e., similar countings. The surveys of the two clusters are complete both at the magnitude and at the periods of the EW binaries. The two clusters have a different stellar content, since NGC 6253 has about members (Montalto et al. 2009), and NGC 6791 about 4900 ± 1000 (De Marchi 2008). The similarity between EW countings in the two clusters supports the hypothesis of an anticorrelation between the frequency of binaries and the richness of the host cluster (Kaluzny & Rucinski 1995). Among the non-member contact binaries, we note that 00441_4 has a period of d, shorter than the shortest contact binary found in the ASAS database (P = d, ASAS , Rucinski 2007) and very similar to the binary with the shortest period known (P = d, V344 in the Lupus field, Weldrake & Bayliss 2008) Semi-detached and detached systems The sample of the semi-detached and detached systems within 8 is composed of five EA, two EB, and two RS CVn stars (lower part of Table A.9). Their periods are shorter than 2.3 d. The star 26902_2 has a high MP, and it is the only case for which we can be very confident about its membership, also confirmed by the positions in the CMDs (Fig. 4, left panels). On the basis of the same criteria, 10340_2 is another probable member. On the other hand, the MP value rules out the membership of 00145_2. No firm conclusion on the membership can be drawn on the other cases Rotational and long-period variables A great number of the new variables discovered in our survey shows the single (RO1) or double (RO2) wave light curves typical of rotational effect. The 10-d time baseline allowed us to detect all the variables with rotational periods shorter than 4 5 days. Other variables show an evident night-to-night variability, but we cannot infer any reliable value for the period. These variables are probably long-period ones (LON). By adopting the same criteria as used in other cases, we selected the RO1 (14 stars), RO2 (2 stars), and LON (16 stars) candidate members of NGC 6253 (Table A.10). Figure 4 plots the CMDs with the positions of all the rotational variables within Page 4 of 18
5 F. De Marchi et al.: Variable stars in NGC 6253 Fig. 3. Top row: colour magnitude diagrams of NGC 6253 with the contact binaries at r < 8 highlighted. The Main Sequences are individuated by fiducial lines. Bottom row: distance moduli of all contact binaries at r < 8 obtained using the P L C relations. We use both (B V)(left panel) and (V I) colours (right panel). The horizontal line represents the distance modulus of the cluster resulting from isochrone fitting (Montalto et al. 2009). Filled circles show the binaries with MPs > 50%; open circles the stars with MPs < 50%, starred points the binaries with unknown membership. The error bars are the errors associated with the M V calculation and include errors in the colour determinations. 8 from the centre and the positions of the long-period variables highlighted (middle and right panels, respectively). We discovered 27 variables in the 8 radius from the centre and 16 of them can be considered candidate members on the basis of the positions on the CMDs and of the MPs (upper part of Table A.10). The stars 10042_2, 11077_2, and 06387_2 have a large MP and also a position on the CMDs compatible with cluster membership. We count 57 rotational variables in the surrounding field, i.e., an occurrence of 0.06 star arcmin 2.This would imply an estimate of 12 field rotational variables along the line of sight of NGC There is a significant difference between the expected and the observed number of rotational variables, and we can infer that several selected candidate members (up to 15) actually belong to the cluster. Considering the short periods of these stars and the old age of the cluster, it is likely that the rotational variables that are cluster members are close, tidally locked binaries. In the same manner, we can estimate 32 LON field variables superposed to NGC In turn this means that up to 9 out of the 41 LON variables discovered in the 8 radius can be considered members of the cluster. These 9 stars should be found among the 16 candidate members listed in Table A A new cataclysmic variable The U Geminorum variable 15877_2 is located at 6.8 from the cluster centre, but unfortunately its MP is not available (Table A.10). In the light curve, the scatter at the quiescence phase suggests some photospheric activity, but no periodicity is detected by analysing these measurements. Such a phase lastes the first 8 days of our survey. After that, its brightness in the R-band increases by about 2.5 mag (Fig. 5). The maximum is not observed because it occurred in daytime. The star 15877_2 Page 5 of 18
6 A&A 509, A17 (2010) Fig. 4. Left panels: CMDs of NGC 6253 with the EA (circles), EB (squares), RS CVn (triangles) variables highlighted. Middle panels: CMDs of NGC 6253 with the rotational single-wave (circles), and double-wave (squares) variables highlighted. Right panels: CMDs of NGC 6253 with the long-period variables located within the 8 -radius circle highlighted. The Main Sequences are individuated by fiducial lines. Fig. 5. Light curve of the new U Gem cataclysmic variable. appears to be similar to the U Geminorum variable 06289_9, classified as a member of NGC 6791 (De Marchi et al. 2007). 5. Conclusions In this paper we have described the first search for variable stars in the open cluster NGC Since the membership probabilities based on the proper motions are not reliable for stars with V > 18, only a few variables could be confirmed directly as cluster members. However, the comparison with the number of contact binaries and rotational variables (both short and long periods) found in a large area surrounding the cluster allowed us to estimate the incidence of these variables within the cluster, too. On the basis of these considerations we propose 35 members of NGC 6253 within the sample of variable stars, though new observations are needed to identify some of them in an unambiguous way. The class of main-sequence rotational variables is the most numerous, as observed in the surrounding field. On the basis of similar observing campaigns, we found the same number of contact binaries in NGC 6253 as were previously found in NGC 6791, thus confirming the anticorrelation between the frequency of binaries and the richness of the cluster (Kaluzny & Rucinski 1995). This anticorrelation is similar to the one found between the frequency of blue stragglers and the total magnitude of the host cluster. Both these facts can lead back to the important effects caused by mass loss in the evolution and in the history of the dynamics of open clusters (Davies et al. 2004; De Marchi et al. 2006). We discovered a new eruptive variable in NGC A single outburst was observed, so we cannot infer any physical characteristic of the system. Since we made the same discovery in NGC 6971 (De Marchi et al. 2007), it seems that continuous surveys on a few nights are very effective in finding these rare and interesting objects. Page 6 of 18
7 F. De Marchi et al.: Variable stars in NGC 6253 Acknowledgements. This work was funded by COFIN 2004 From stars to planets: accretion, disk evolution and planet formation by MIUR and by PRIN 2006 From disk to planetary systems: understanding the origin and demographics of solar and extrasolar planetary systems by INAF. We thank the anonymous referee for careful reading and useful suggestions, and J. Vialle for checking the English form. References Alard, C. 2000, A&A, 144, 363 Alard, C., & Lupton, R. H. 1998, ApJ, 503, 325 Anthony-Twarog, B. J., Twarog, B. A., & Mayer, L. 2007, AJ, 133, 1585 Bragaglia, A., Tessicini, G., Tosi, M., Marconi, G., & Munari, U. 1997, MNRAS, 284, 477 Carpino, M., Milani, A., & Nobili, A. M. 1987, A&A, 181, 182 Carretta, E., Bragaglia, A., Tosi, M., & Marconi, G. 2000, in Stellar Clusters and Associations: Convection, Rotation, and Dynamos, ed. R. Pallavicini, G. Micela, & S. Sciortino, ASPC, 198, 273 Carretta, E., Bragaglia, A., & Gratton, R. 2007, A&A, 473, 129 Davies, M. B., Piotto, G., & De Angeli, F. 2004, MNRAS, 349, 129 De Marchi, F. 2008, Ph.D. Thesis, University of Padova De Marchi, F., De Angeli, F., Piotto, G., Carraro, G., & Davies, M. B. 2006, A&A, 459, 489 De Marchi, F., Poretti, E., Montalto, M., et al. 2007, A&A, 471, 51 Kaluzny, J., & Rucinski, S. M. 1995, A&AS, 114, 1 Ferraz-Mello, S. 1981, AJ, 86, 4 Momany, Y., Vandame, B., Zaggia, S., et al. 2001, A&A, 379, 436 Montalto, M., Piotto, G., Desidera, S., et al. 2007, A&A, 470, 1137 Montalto, M., Piotto, G., Desidera, S., et al. 2009, A&A, 505, 1129 Piatti, A. E., Clariá, J. J., Bica, E., Geisler, D., & Minniti, D. 1998, AJ, 116, 801 Poretti, E. 2001, A&A, 371, 986 Poretti, E., Clementini, G., Held, E., et al. 2008, ApJ, 685, 947 Rucinski, S. M. 2003, New Astron. Rev., 48, 703 Rucinski, S. M. 2007, MNRAS, 382, 393 Sagar, R., Munari, U., & de Boer, K. S. 2001, MNRAS, 327, 23 Sestito, P., Randich, S., & Bragaglia, A. 2007, A&A, 465, 185 Stellingwerf, R. F. 1978, ApJ, 224, 953 Stetson, P. 1998, PASP, 106, 250 Tamuz, O., Mazeh, T., & Zucker, S. 2005, MNRAS, 356, 1466 Twarog, B. R., Anthony-Twarog, B. J., & De Lee, N. 2003, AJ, 125, 1383 Vaníček, P. 1971, Ap&SS, 12, 10 Vasilevskis, S., Klemola, A., & Preston, G. 1958, AJ, 63, 387 Weldrake, D. T. F., & Bayliss, D. D. R. 2008, AJ, 135, 649 Appendix A: Tables This Appendix includes the tables listing all the variables discovered in our survey of NGC 6253 and its surrounding field. The epochs of maximum or minimum brightness are expressed as HJD in the columns T max and T min. 1. Pulsating variables: Table A.1; 2. EW-type variables: Table A.2; 3. EA-type variables: Table A.3; 4. EB-type variables: Table A.4; 5. RS-CVn variables: Table A.5; 6. rotational single-wave variables: Table A.6; 7. rotational double-wave variables: Table A.7; 8. long-period variables: Table A.8. The binary systems considered as candidate members of NGC 6253 are listed in Table A.9. The rotational and longperiod variables considered as candidate members of NGC 6253 are listed in Table A.10. Table A.1. Pulsating variables. Star ID Type α 2000 δ 2000 R V B V V I T max Period Ampl. Distance MP 16334_ DSCT _ DSCT _ DSCT _ DSCT _ DSCT _ DSCT _6 DSCT _ DSCT _ DSCT _ DSCT _ DSCT _ BCEP _ HADS _ HADS _ HADS _ HADS _ RR _ RR _ RR _ RR Page 7 of 18
8 Table A.2. Contact binaries, W Ursae Maioris (EW) systems. A&A 509, A17 (2010) Star ID α 2000 δ 2000 R max V B V V I T min Period Ampl. Distance MP 00441_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ * 16816_ _ _ _ _ _ _ Page 8 of 18
9 F. De Marchi et al.: Variable stars in NGC 6253 Table A.2. continued. Star ID α 2000 δ 2000 R max V B V V I T min Period Ampl. Distance MP 09914_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ * 10995_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Page 9 of 18
10 A&A 509, A17 (2010) Table A.2. continued. Star ID α 2000 δ 2000 R max V B V V I T min Period Ampl. Distance MP 22576_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ * 05435_ _ _ _ _ _ _ * 01618_ _ _ _ _ _ _ _ _ Page 10 of 18
Variable stars in the open cluster NGC 6791 and its surrounding field ABSTRACT
A&A 471, 515 526 (2007) DOI: 10.1051/0004-6361:20077386 c ESO 2007 Astronomy & Astrophysics Variable stars in the open cluster NGC 6791 and its surrounding field F. De Marchi 1,E.Poretti 2,M.Montalto 1,
More informationCharacterization of variable stars using the ASAS and SuperWASP databases
Characterization of variable stars using the ASAS and SuperWASP databases Derck P. Smits Dept of Mathematical Sciences, PO Box 392, UNISA, 0003, South Africa E-mail: smitsdp@unisa.ac.za Abstract. A photographic
More informationTNG photometry of the open cluster NGC 6939
Mem. S.A.It. Vol. 75, 19 c SAIt 2004 Memorie della TNG photometry of the open cluster NGC 6939 G. Andreuzzi 1, A. Bragaglia 2, M. Tosi 2 and G. Marconi 3 1 INAF Osservatorio Astronomico di Roma, via Frascati
More informationVariable stars in the field of open cluster NGC 2126
Research in Astron. Astrophys. 2009 Vol. 9 No. 7, 791 802 http://www.raa-journal.org http://www.iop.org/journals/raa Research in Astronomy and Astrophysics Variable stars in the field of open cluster NGC
More informationClusters AgeS Experiment. New variable stars in the globular cluster M 22
A&A 373, 899 904 (2001) DOI: 10.1051/0004-6361:20010599 c ESO 2001 Astronomy & Astrophysics Clusters AgeS Experiment. New variable stars in the globular cluster M 22 J. Kaluzny 1 and I. B. Thompson 2 1
More informationNew variable stars in the globular cluster NGC 288
ASTRONOMY & ASTROPHYSICS OCTOBER II 1997, PAGE 337 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 125, 337-341 (1997) New variable stars in the globular cluster NGC 288 J. Kaluzny 1,W.Krzemiński 2, and
More informationRECLASSIFICATION OF ROTSE-I SCUTI STARS WITH MULTIBAND PHOTOMETRY AND FOURIER DECOMPOSITION
The Astronomical Journal, 128:1847 1856, 2004 October # 2004. The American Astronomical Society. All rights reserved. Printed in U.S.A. RECLASSIFICATION OF ROTSE-I SCUTI STARS WITH MULTIBAND PHOTOMETRY
More informationCyclic variations in the periods of RR Lyr stars arxiv: v1 [astro-ph.sr] 29 Jan 2018
Cyclic variations in the periods of RR Lyr stars arxiv:1801.09702v1 [astro-ph.sr] 29 Jan 2018 Ennio Poretti 1 2 3, Jean-Francois Le Borgne 4 5 3, Alain Klotz 4 5 3, Monica Rainer 1 6 and Mercedes Correa
More informationNGC 2660 revisited. 1520, DK 8000 Aarhus C, Denmark. 1520, DK 8000 Aarhus C, Denmark
Comm. in Asteroseismology Vol. 148, 2006 NGC 2660 revisited T.E. Mølholt 1,S.Frandsen 1, F. Grundahll 1,2 and L. Glowienka 1 1 Dept. of Physics and Astronomy, University of Aarhus, Ny Munkegade, Bygn.
More informationarxiv:astro-ph/ v1 12 Feb 2004
Planets in Stellar Clusters Extensive Search. II. Discovery of 57 Variables in the Cluster NGC 2158 with Millimagnitude Image Subtraction Photometry. arxiv:astro-ph/0402306v1 12 Feb 2004 B. J. Mochejska
More informationCanberra, Australia Received September 26, 2014 ABSTRACT
ACTA ASTRONOMICA Vol. 64 (2014) pp. 233 246 The Clusters AgeS Experiment (CASE). Analysis of the Detached Eclipsing Binary V15 in the Metal-Rich Open Cluster NGC 6253 M. R o z y c z k a 1, J. K a l u z
More informationReddening map of the Large Magellanic Cloud bar region. A. Subramaniam
A&A 430, 421 426 (2005) DOI: 10.1051/0004-6361:20041279 c ESO 2005 Astronomy & Astrophysics Reddening map of the Large Magellanic Cloud bar region A. Subramaniam Indian Institute of Astrophysics, II Block,
More informationarxiv: v1 [astro-ph.sr] 1 Jul 2012
BD+36 3317: An Algol Type Eclipsing Binary in Delta Lyrae Cluster arxiv:1207.0194v1 [astro-ph.sr] 1 Jul 2012 O. Özdarcan, E. Sipahi, H. A. Dal Ege University, Science Faculty, Department of Astronomy and
More informationNTT V, I, z photometry of the metal-rich bulge globular cluster Terzan 6
ASTRONOMY & ASTROPHYSICS MAY I 1997, PAGE 483 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 122, 483-488 (1997) NTT V, I, z photometry of the metal-rich bulge globular cluster Terzan 6 B. Barbuy 1,
More informationA CCD BV I color-magnitude study of the metal-rich globular cluster NGC 5927,
ASTRONOMY & ASTROPHYSICS OCTOBER II 1996, PAGE 191 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 119, 191-197 (1996) A CCD BV I color-magnitude study of the metal-rich globular cluster NGC 5927, N.
More informationThe Plato Input Catalog (PIC)
The Plato Input Catalog (PIC) Giampaolo Piotto and the WP130000 group Dipartimento di Fisica e Astronomia Universita di Padova Because of the huge size of PLATO field (~2124 sq deg) and the consequent
More informationA photometric study of the intermediate age open cluster King 5
A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are: 06 (03.11.1; 16.06.1; 19.06.1; 19.37.1; 19.53.1; 19.63.1) ASTRONOMY AND ASTROPHYSICS A photometric study of the intermediate
More informationConcepción, Chile ABSTRACT
1 The Optical Gravitational Lensing Experiment. Search for Planetary and Low-Luminosity Object Transits in the Galactic Disk. Results of 2001 Campaign Supplement A. Udalski 1, K. Żebruń 1, M. S z y m a
More informationV551 Aur, an oea binary with g-mode pulsations?
Research in Astron. Astrophys. 2012 Vol. 12 No. 6, 671 677 http://www.raa-journal.org http://www.iop.org/journals/raa Research in Astronomy and Astrophysics V551 Aur, an oea binary with g-mode pulsations?
More informationarxiv:astro-ph/ v1 10 Oct 2005
Mon. Not. R. Astron. Soc. 000, 1?? (2005) Printed 5 February 2008 (MN LATEX style file v2.2) CCD photometry of distant open clusters NGC 2425, Haffner 10 and Czernik 29 arxiv:astro-ph/0510274v1 10 Oct
More informationHigh quality seeing V, I and Gunn z imaging of Terzan 4: a blue horizontal branch bulge globular cluster
Astron. Astrophys. 319, 850 854 (1997) ASTRONOMY AND ASTROPHYSICS High quality seeing V, I and Gunn z imaging of Terzan 4: a blue horizontal branch bulge globular cluster S. Ortolani 1, B. Barbuy 2, and
More informationBuilding the cosmic distance scale: from Hipparcos to Gaia
The Fundamental Distance Scale: state of the art and the Gaia perspectives 3-6 May 2011 Building the cosmic distance scale: from Hipparcos to Gaia Catherine TURON and Xavier LURI 1 ESA / ESO-H. Heyer Fundamental
More informationV, I photometry of the metal-rich bulge globular cluster Terzan 2
Astron. Astrophys. 326, 614 619 (1997) ASTRONOMY AND ASTROPHYSICS V, I photometry of the metal-rich bulge globular cluster Terzan 2 S. Ortolani 1, E. Bica 2, and B. Barbuy 3 1 Università di Padova, Dept.
More informationV, I photometry of the bulge metal-rich globular clusters NGC 6380 and Terzan 12
ASTRONOMY & ASTROPHYSICS FEBRUARY I 1998, PAGE 471 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 127, 471-477 (1998) V, I photometry of the bulge metal-rich globular clusters NGC 6380 and Terzan 12
More informationOn the double-mode RR Lyrae variables of the Sculptor dwarf galaxy
A&A 375, 469 475 (2001) DOI: 10.1051/0004-6361:20010880 c ESO 2001 Astronomy & Astrophysics On the double-mode RR Lyrae variables of the Sculptor dwarf galaxy G. Kovács Konkoly Observatory, PO Box 67,
More informationCCD photometry of variable stars in the field of the globular cluster NGC 6397
ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 122, 1-7 (1997) APRIL I 1997, PAGE1 CCD photometry of variable stars in the field of the globular cluster NGC 6397 J. Kaluzny Warsaw
More information186 to indicate the goodness of the period. If my examination of the data phased to the test period finds that the lightcurve appears appropriately pe
Chapter 5 Periodic Variables and Binary Sequences 5.1 Periodic Variable Stars The primary purpose of our project is to search for brightness changes resulting from photospheric stellar activity on the
More informationThe Milky Way Formation Timescale
Mem. S.A.It. Vol. 75, 13 c SAIt 2004 Memorie della The Milky Way Formation Timescale A. Aparicio 1,2, A. Rosenberg 2, G. Piotto 3, I. Saviane 4 and A. Recio-Blanco 3 1 Departamento de Astrofisica, Universidad
More informationMULTIPLE STELLAR POPULATIONS IN 47 TUCANAE (AND NGC
MULTIPLE STELLAR POPULATIONS IN 47 TUCANAE (AND NGC ( 6397 Antonino P. Milone Instituto de Astrofisica de Canarias coworkers: Anna F. Marino (MPA-Garching, Germany) Ivan R. King (Univ. of Washington, (
More informationOGLE-TR-56. Guillermo Torres, Maciej Konacki, Dimitar D. Sasselov and Saurabh Jha INTRODUCTION
OGLE-TR-56 Guillermo Torres, Maciej Konacki, Dimitar D. Sasselov and Saurabh Jha Harvard-Smithsonian Center for Astrophysics Caltech, Department of Geological and Planetary Sciences University of California
More informationarxiv:astro-ph/ v1 21 Feb 2001
May 30, 2018 A New SX Phe Star in the Globular Cluster M15 Young-Beom Jeon 1, Seung-Lee Kim arxiv:astro-ph/0102351v1 21 Feb 2001 Korea Astronomy Observatory, Taejeon, 305-348, KOREA Email: ybjeon@boao.re.kr
More informationA Reinvestigation of the Physical Properties of Pismis 3 based on 2MASS Photometry
Chin. J. Astron. Astrophys. Vol. 8 (2008), No. 3, 362 368 (http://www.chjaa.org) Chinese Journal of Astronomy and Astrophysics A Reinvestigation of the Physical Properties of Pismis 3 based on 2MASS Photometry
More informationarxiv: v4 [astro-ph] 18 Jun 2008
Chinese Journal of Astronomy and Astrophysics manuscript no. (L A TEX: chjaa.tex; printed on April 18, 2017; 6:18) Chin. J. Astron. Astrophys. Vol. 8 (2008), No. 3, 362 Received 2007 May 31; accepted 2008
More informationThe optical gravitational lensing experiment. Variable stars in globular clusters
ASTRONOMY & ASTROPHYSICS OCTOBER II 1997, PAGE 343 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 125, 343-353 (1997) The optical gravitational lensing experiment. Variable stars in globular clusters
More informationBH 176 and AM-2: globular or open clusters?*
1995A&A...3..726O Astron. Astrophys. 3, 726-73 I ( 1995) ASTRONOMY AND ASTROPHYSICS BH 176 and AM-2: globular or open clusters?* S. Ortolani 1, E. Bica 2, and B. Barbuy 3 1 Universita di Padova, Dipartimento
More informationNear IR photometry of the old open clusters Berkeley 17 and Berkeley 18
Astron. Astrophys. 343, 825 830 (1999) Near IR photometry of the old open clusters Berkeley 17 and Berkeley 18 Probing the age of the Galactic Disc Giovanni Carraro 1, Antonella Vallenari 2,Léo Girardi
More informationThe Composition of the Old, Metal-Rich Open Cluster, NGC 6791
The Composition of the Old, Metal-Rich Open Cluster, NGC 6791 Liz Jensen --- Smith College, REU at IFA, University of Hawaii 2006 Mentor: Ann M. Boesgaard --- Institute for Astronomy, University of Hawaii
More informationarxiv: v1 [astro-ph] 8 Sep 2007
Variable stars in the Open Cluster M11 (NGC 6705) J.-R. Koo arxiv:0709.1180v1 [astro-ph] 8 Sep 2007 Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764, Korea; and
More informationDiscovery of a deep, low mass ratio overcontact binary GSC
Research in Astron. Astrophys. 2014 Vol. X No. XX, 000 000 http://www.raa-journal.org http://www.iop.org/journals/raa Research in Astronomy and Astrophysics Discovery of a deep, low mass ratio overcontact
More informationMembership determination of open cluster NGC 188 based on the DBSCAN clustering algorithm
RAA 2014 Vol. 14 No. 2, 159 164 doi: 10.1088/1674 4527/14/2/004 http://www.raa-journal.org http://www.iop.org/journals/raa Research in Astronomy and Astrophysics Membership determination of open cluster
More informationarxiv: v1 [astro-ph] 2 Jul 2007
Mon. Not. R. Astron. Soc. 000, 1?? (2007) Printed 24 October 2018 (MN LATEX style file v2.2) ariable stars in the field of the old open cluster Melotte 66 arxiv:0707.0207v1 [astro-ph] 2 Jul 2007 K. Zloczewski
More informationCCD photometry of δ Scuti stars 7 Aql and 8 Aql
Comm. in Asteroseismology Vol. 153, 2008 CCD photometry of δ Scuti stars 7 Aql and 8 Aql Abstract L. Fox Machado 1, R. Michel 1, M. Álvarez1, L. Parrao 2, A. Castro 1, and J. H. Peña 2 1 Observatorio Astronómico
More informationDiscovery of a deep, low mass ratio overcontact binary GSC
RAA 2015 Vol. 15 No. 6, 889 895 doi: 10.1088/1674 4527/15/6/011 http://www.raa-journal.org http://www.iop.org/journals/raa Research in Astronomy and Astrophysics Discovery of a deep, low mass ratio overcontact
More information2 Princeton University Observatory, Princeton, NJ , USA
ACTA ASTRONOMICA Vol. 49 (1999) pp. 45 57 The Optical Gravitational Lensing Experiment. Cepheids in the Magellanic Clouds. II. Single-Mode Second Overtone Cepheids in the Small Magellanic Cloud by A. U
More informationCCD photometry of variable stars in the globular cluster NGC 288
ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 120, 83-88 (1996) NOVEMBER II 1996, PAGE83 CCD photometry of variable stars in the globular cluster NGC 288 J. Kaluzny Warsaw University
More informationarxiv: v2 [astro-ph] 4 Nov 2008
Comm. in Asteroseismology Vol. number, publication date (will be inserted in the production process) On the nature of HD 207331: a new δ Scuti variable arxiv:0810.0476v2 [astro-ph] 4 Nov 2008 L.Fox Machado
More informationarxiv: v1 [astro-ph.sr] 6 Jul 2013
On The Period Determination of ASAS Eclipsing Binaries L. Mayangsari a,, R. Priyatikanto a, M. Putra a,b a Prodi Astronomi Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung, Jawa Barat, Indonesia
More informationarxiv: v1 [astro-ph.ga] 3 Mar 2014
CCD BVRI and 2MASS Photometry of the Poorly Studied Open Cluster NGC 6631 arxiv:1403.0546v1 [astro-ph.ga] 3 Mar 2014 Tadross, A. L. a, Bendary, R. a, Priya, H. b, Essam, A. a, Osman, A. a a National Research
More informationThe nature of the star clusters ESO 93 SC08 and ESO 452 SC11
ASTRONOMY & ASTROPHYSICS APRIL II 1999, PAGE 363 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 136, 363 372 (1999) The nature of the star clusters ESO 93 SC08 and ESO 452 SC11 E. Bica 1, S. Ortolani
More informationA New Analysis in the Field of the Open Cluster Collinder 223
Chin. J. Astron. Astrophys. Vol. 4 (2004), No. 1, 67 74 ( http: /www.chjaa.org or http: /chjaa.bao.ac.cn ) Chinese Journal of Astronomy and Astrophysics A New Analysis in the Field of the Open Cluster
More informationDwarf spheroidal satellites of M31: Variable stars and stellar populations
Dwarf spheroidal satellites of M31: Variable stars and stellar populations Felice Cusano INAF-Osservatorio Astronomico di Bologna LBT Team Italy collaborators: Gisella Clementini, Alessia Garofalo, Michele
More informationCharacterisation of the open cluster M67
Characterisation of the open cluster M67 Author: Facultat de Física, Universitat de Barcelona, Diagonal 645, 828 Barcelona, Spain. Advisor: Carme Jordi Nebot, Eduard Masana Fresno, Lola Balaguer Núñez
More informationPhotometric Techniques II Data analysis, errors, completeness
Photometric Techniques II Data analysis, errors, completeness Sergio Ortolani Dipartimento di Astronomia Universita di Padova, Italy. The fitting technique assumes the linearity of the intensity values
More informationNEW VARIABLE STARS IN THE GLOBULAR CLUSTER NGC
Journal of the Southeastern Association for Research in Astronomy, 6, 63-71, 2012 July 10 c 2012. Southeastern Association for Research in Astronomy. All rights reserved. NEW VARIABLE STARS IN THE GLOBULAR
More informationA search for SX Phe stars among Kepler δ Scuti stars
Mon. Not. R. Astron. Soc. 426, 2413 2418 (2012) doi:10.1111/j.1365-2966.2012.21957.x A search for SX Phe stars among Kepler δ Scuti stars L. A. Balona 1 and J. M. Nemec 2 1 South African Astronomical Observatory,
More informationProper motion measurements as indicators of binarity in open clusters. E. Bica and C. Bonatto
A&A 431, 43 51 (25) DOI:.51/4-6361:24223 c ESO 25 Astronomy & Astrophysics Proper motion measurements as indicators of binarity in open clusters E. Bica and C. Bonatto Universidade Federal do Rio Grande
More informationGSC : an RR Lyrae star with a ceasing Blazhko effect and three new variables in the field.
GSC 02626-00896: an RR Lyrae star with a ceasing Blazhko effect and three new variables in the field. Rainer Gröbel 1, 2 1) DE- 90542 Eckental, Germany rainer.groebel@web.de 2) Bundesdeutsche Arbeitsgemeinschaft
More informationarxiv:astro-ph/ v1 26 Nov 2004
13 Color Photometry of Open Cluster M48 Zhen-Yu Wu, Xu Zhou, Jun Ma, Zhao-Ji Jiang, Jian-Sheng Chen National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, arxiv:astro-ph/0411711v1
More informationHD Transits HST/STIS First Transiting Exo-Planet. Exoplanet Discovery Methods. Paper Due Tue, Feb 23. (4) Transits. Transits.
Paper Due Tue, Feb 23 Exoplanet Discovery Methods (1) Direct imaging (2) Astrometry position (3) Radial velocity velocity Seager & Mallen-Ornelas 2003 ApJ 585, 1038. "A Unique Solution of Planet and Star
More informationTHE ABSOLUTE MAGNITUDE OF FIELD METAL-POOR HORIZONTAL BRANCH STARS
Mon. Not. R. Astron. Soc. 000, 000 000 (1997) THE ABSOLUTE MAGNITUDE OF FIELD METAL-POOR HORIZONTAL BRANCH STARS Raffaele G. Gratton Osservatorio Astronomico di Padova, Vicolo dell Osservatorio 5, 35122
More informationNew frequency analyses of the multiperiodic δ Scuti variables CR Lyn and GG UMa
Comm. in Asteroseismology ol. 148, 2006 New frequency analyses of the multiperiodic δ Scuti variables CR Lyn and GG UMa C.W. Robertson 1,P.anCauteren 2, P. Lampens 3,E.García-Melendo 4,R. Groenendaels
More informationPeriod and amplitude changes in the δ Scuti star V 1162 Orionis
Astron. Astrophys. 354, 589 594 (2000) ASTRONOMY AND ASTROPHYSICS Period and amplitude changes in the δ Scuti star V 1162 Orionis T. Arentoft and C. Sterken University of Brussels (VUB), Pleinlaan 2, 1050
More informationReanalysis of the OGLE-I Observations with the Image Subtraction Method. I. Galactic Bar Fields MM1-A, MM1-B, MM7-A, and MM7-B 1
ACTA ASTRONOMICA Vol. 53 (2003) pp. 27 50 Reanalysis of the OGLE-I Observations with the Image Subtraction Method. I. Galactic Bar Fields MM1-A, MM1-B, MM7-A, and MM7-B 1 by A. P i g u l s k i, Z. K o
More informationarxiv: v1 [astro-ph.ga] 30 Apr 2010
Astronomy & Astrophysics manuscript no. 13749 c ESO 2010 May 3, 2010 Letter to the Editor Evidence of the inhomogeneity of the stellar population in the differentially reddened globular cluster NGC 3201.
More information0HA, UK Received December 15, 2009 ABSTRACT
ACTA ASTRONOMICA Vol. 60 (10) pp. 1 16 The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. VI. Delta Scuti Stars in the Large Magellanic Cloud 1 R. P o l e s k i 1, I.
More informationTHE ABSOLUTE DIMENSIONS OF THE OVERCONTACT BINARY FI BOOTIS
The Astronomical Journal, 132:1153Y1157, 2006 September # 2006. The American Astronomical Society. All rights reserved. Printed in U.S.A. A THE ABSOLUTE DIMENSIONS OF THE OVERCONTACT BINARY FI BOOTIS Dirk
More informationColour Magnitude analysis of five old open clusters
A&A 437, 531 536 (2005) DOI: 10.1051/0004-6361:20042326 c ESO 2005 Astronomy & Astrophysics Colour Magnitude analysis of five old open clusters S. Ortolani 1,E.Bica 2, and B. Barbuy 3 1 Università di Padova,
More informationTaurus stars membership in the Pleiades open cluster
Taurus stars membership in the Pleiades open cluster Tadross, A. L., Hanna, M. A., Awadalla, N. S. National Research Institute of Astronomy & Geophysics, NRIAG, 11421 Helwan, Cairo, Egypt ABSTRACT In this
More informationThe red giant branches of Galactic globular clusters in the [(V I) 0,M V ] plane: metallicity indices and morphology
Astron. Astrophys. 355, 966 978 (2000) The red giant branches of Galactic globular clusters in the [(V I) 0,M V ] plane: metallicity indices and morphology ASTRONOMY AND ASTROPHYSICS I. Saviane 1, A. Rosenberg
More informationGlobular Cluster Ages and Strömgren CCD Photometry
Globular Cluster Ages and Strömgren CCD Photometry Frank Grundahl 1 University of Victoria, Department of Physics and Astronomy PO Box 3055, Victoria, BC, V8W 3P6, Canada Abstract. Strömgren uvby CCD photometry
More information2 Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile,
ACTA ASTRONOMICA Vol. 58 (2008) pp. 121 130 CURiuos Variables Experiment (CURVE): Variable Stars in the Metal-Poor Globular Cluster M56 P. P i e t r u k o w i c z 1,2, A. O l e c h 1, P. K ę d z i e r
More informationGaia News:Counting down to launch A. Vallenari. INAF, Padova Astronomical Observatory on behalf of DPACE
Gaia News:Counting down to launch A. Vallenari INAF, Padova Astronomical Observatory on behalf of DPACE Outline Gaia Spacecraft status The Gaia sky Gaia open and globular clusters From data to science:
More informationA new search for planet transits in NGC 6791 ABSTRACT
A&A 470, 1137 1156 (2007) DOI: 10.1051/0004-6361:20066199 c ESO 2007 Astronomy & Astrophysics A new search for planet transits in NGC 6791 M. Montalto 1, G. Piotto 1, S. Desidera 2,F.DeMarchi 1,H.Bruntt
More informationarxiv: v1 [astro-ph.sr] 15 Jun 2016
Research in Astron. Astrophys. XXXX Vol. X No. XX, 000 000 http://www.raa-journal.org http://www.iop.org/journals/raa Research in Astronomy and Astrophysics arxiv:1606.04792v1 [astro-ph.sr] 15 Jun 2016
More informationASTRONOMY AND ASTROPHYSICS. B and V photometry of the metal-rich bulge globular cluster NGC 6304
Astron. Astrophys. 357, 495 500 (2000) B and V photometry of the metal-rich bulge globular cluster NGC 6304 ASTRONOMY AND ASTROPHYSICS S. Ortolani 1, Y. Momany 1, E. Bica 2, and B. Barbuy 3 1 Università
More informationLight Curve Analysis of GSC and GSC
Light Curve Analysis of GSC 2750-0054 and GSC 03208-02644 M. M. Elkhateeb,2 and M. I. Nouh,2 E-mail: abdo_nouh@hotmail.com Physics Department, College of Science, Northern Border University, Arar, Saudi
More informationThe luminosity and mass function of the globular cluster NGC 1261
Astron. Astrophys. 331, 541 549 (1998) ASTRONOMY AND ASTROPHYSICS The luminosity and mass function of the globular cluster NGC 1261 M. Zoccali 1, G. Piotto 1, S.R. Zaggia 2, and M. Capaccioli 2 1 Dipartimento
More informationarxiv:astro-ph/ v1 3 Sep 2003
Astronomy & Astrophysics manuscript no. July 23, 2013 (DOI: will be inserted by hand later) Asteroseismology of HADS stars: V974 Oph, a radial pulsator flavoured by nonradial components E. Poretti arxiv:astro-ph/0309093v1
More informationCluster AgeS Experiment. CCD photometry of SX Phoenicis variables in the globular cluster M 55
A&A 367, 48 58 (2) DOI: /4-636:2349 c ESO 2 Astronomy & Astrophysics Cluster AgeS Experiment. CCD photometry of SX Phoenicis variables in the globular cluster M 55 W. Pych,J.Kaluzny,W.Krzeminski,2, A.
More informationImpact of stellar micro-variability on transit detection from space
Chapter 5 Impact of stellar micro-variability on transit detection from space 5.1 Introduction This chapter summarises a number of simulations which were performed with the tools developed in the previous
More informationVariable central stars of young Planetary Nebulae
ASTRONOMY & ASTROPHYSICS MARCH II 1999, PAGE 493 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 135, 493 498 (1999) Variable central stars of young Planetary Nebulae A photometric study of the central
More informationThe cosmic distance scale
The cosmic distance scale Distance information is often crucial to understand the physics of astrophysical objects. This requires knowing the basic properties of such an object, like its size, its environment,
More informationLynga 7: a new disk globular cluster?*
Astron. Astrophys. 273, 415-4 (93) ASTRONOMY AND ASTROPHYSICS Lynga 7: a new disk globular cluster?* S. Ortolani 1, E. Bica 2, and B. Barbuy 3 1 Universita di Padova, Dept. di Astronomia, Vicolo dell'osservatorio
More informationParallaxes with Hubble Space Telescope
Parallaxes with Hubble Space Telescope How Bayes (and Bill) Helped G. Fritz Benedict and Barbara E. McArthur McDonald Observatory 10 June 2004 University of Texas 1 Outline Astrometry with HST A Recent
More informationTerzan 3 and IC 1276 (Palomar 7): Two metal-rich bulge globular clusters uncovered
ASTRONOMY & ASTROPHYSICS NOVEMBER I 1998, PAGE 333 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 132, 333 340 (1998) Terzan 3 and IC 1276 (Palomar 7): Two metal-rich bulge globular clusters uncovered
More informationarxiv:astro-ph/ v1 22 Nov 2000
**TITLE** ASP Conference Series, Vol. **VOLUME**, **PUBLICATION YEAR** **EDITORS** OAO1657 415 : A Missing Link in High Mass X-ray Binaries? arxiv:astro-ph/0011401v1 22 Nov 2000 D.H. Maxwell, A.J. Norton
More informationA SCUTI DISTANCE TO THE LARGE MAGELLANIC CLOUD 1
The Astronomical Journal, 133:2752Y2763, 2007 June # 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A. A A SCUTI DISTANCE TO THE LARGE MAGELLANIC CLOUD 1 D. Harold McNamara
More informationWOCS Long-Term Variability in Open Cluster NGC 2141
WOCS Long-Term Variability in Open Cluster NGC 2141 A. M. Widhalm 1,2 Physics and Astronomy Department, University of Southern California, Los Angeles, CA 90007 and S. Kafka Cerro Tololo Inter-American
More informationarxiv:astro-ph/ v1 8 Jul 2001
Astronomy & Astrophysics manuscript no. (will be inserted by hand later) A variable star survey of the open cluster M37 L.L. Kiss 1,4, Gy. Szabó 1, K. Sziládi 1,4, G. Fűrész 1, K. Sárneczky 2,4, and B.
More informationFirst Orbital Solution and Evolutionary State for the Newly Discovered Eclipsing Binaries USNO-B and GSC
First Orbital Solution and Evolutionary State for the Newly Discovered Eclipsing Binaries USNO-B1.0 1091-0130715 and GSC-03449-0680 M. M. Elkhateeb 1, 2, M. I. Nouh 1, 2 and R. H. Nelson 1 Astronomy Department,
More informationDelta Scuti stars: Observational aspects
Comm. in Asteroseismology Vol. 150, 2007 Delta Scuti stars: Observational aspects M. Breger Institute of Astronomy, University of Vienna, 1180 Vienna, Austria Abstract The review concentrates on several
More informationExtra RR Lyrae Stars in the Original Kepler Field of View
Extra RR Lyrae Stars in the Original Kepler Field of View Ottó Hanyecz 1 2 and Róbert Szabó 2 1. Eötvös Loránd University, Budapest, Hungary 2. MTA CSFK, Konkoly Observatory, Budapest, Hungary Our previous
More informationSUPPLEMENTARY INFORMATION
1. Identification of classical Cepheids: We identified three classical Cepheids amongst the 45 short-period variables discovered. Our sample includes classical Cepheids, type II Cepheids, eclipsing binaries
More informationPoS(extremesky2009)103
The study of the nature of sources AX J1749.1 2733 and AX J1749.2 2725 D. I. Karasev Space Research Institute, Profsoyuznaya str. 84/32, Moscow 117997, Russia E-mail: dkarasev@iki.rssi.ru Space Research
More informationSynergies between E-ELT and space instrumentation for extrasolar planet science
Synergies between E-ELT and space instrumentation for extrasolar planet science Raffaele Gratton and Mariangela Bonavita INAF Osservatorio Astronomico di Padova - ITALY Main topics in exo-planetary science
More informationThe Pulsation Properties of the Double-Mode RR Lyrae Variable V79 in Messier 3
336 The Pulsation Properties of the Double-Mode RR Lyrae Variable V79 in Messier 3 Christine M. Clement Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON, M5S 3H8, Canada Mike
More informationarxiv:astro-ph/ v1 20 Apr 2004
Mon. Not. R. Astron. Soc. 000, 1 7 (2004) Printed 13 November 2017 (MN LATEX style file v2.2) The Red Giant Branch in Near-Infrared Colour-Magnitude Diagrams. II: The luminosity of the Bump and the Tip
More informationBV R photometry of the star TU UMi
BV R photometry of the star TU UMi Diana Kjurkchieva 1, Dinko Dimitrov 2, Sunay Ibryamov 1 1 University of Shumen, Bulgaria 2 Institute of Astronomy, Bulgarian Academy of Sciences d.kyurkchieva@shu-bg.net;
More informationA spectroscopic study of RGB stars in the globular cluster NGC 2808 with FLAMES
Mem. S.A.It. Suppl. Vol. 5, 59 c SAIt 2004 Memorie della Supplementi A spectroscopic study of RGB stars in the globular cluster NGC 2808 with FLAMES C. Cacciari, A. Bragaglia and E. Carretta INAF Osservatorio
More informationarxiv: v1 [astro-ph] 22 Dec 2008
Astronomy & Astrophysics manuscript no. olmo ref c ESO 2008 December 22, 2008 Letter to the Editor Double mode RR Lyrae stars in Omega Centauri A. Olech 1 and P. Moskalik 1 arxiv:0812.4173v1 [astro-ph]
More information